Photochemical reactions in snow have recently witnessed an unprecedented surge of interest. In recent investigations, it is seen that production and significant release of CO flux is from snow covered region. On the basis of measurements made at Maitri, Antarctica, it has been observed a systematical diurnal cycle coinciding with the diurnal cycle of solar actinic radiation. This variation implies that photochemical production of CO is active in the snow covered region of Antarctica. It is expected that organic matter is trapped in snow and especially photochemical destruction of formaldehyde (HCHO) is probably the major substrate of the photochemical formation of CO when exposes to sunlight. The study shows that Polar regions may act as one of the strong source of carbonmonoxide. The measurements of CO over Antarctica support the finding of earlier investigators that substantial abundance of HCHO is produced by a flux from the snow.

Similar type of CO measurements over Arctic were carried out to study snow-pack production of carbon monoxide and its diurnal variability during First Indian Arctic Winter phase Expedition (2nd – 31st March, 2008). Along with these measurements studies were carried out on Black Carbon, aerosol number-size distribution, AOD, water vapour and collected air samples over Arctic region. The variation of CO in ppbv over Arctic is presented in Fig. 6.14.